Outgoing UN High Commissioner Filippo Grandi on Friday appealed for the creation of a clear mechanism for European states to share out the burden of migrants rescued at sea rather than work on a case by case basis.

Those arriving "must be shared around Europe. There must be a foreseeable mechanism. We cannot deal on a boat by boat basis," the UN refugee chief told a news conference after two days of talks with authorities in his native Italy, AFP reported.

Italy has closed its ports to NGOs rescuing migrants in the Mediterranean and has been increasingly reluctant to take in those brought to shore in its own vessels, making reception conditional on those brought to shore being offloaded to other EU states.

"We are not talking about incredible figures – if Libya can deal with a million refugees then Europe can manage a few tens of thousands," Grandi said.

He added that between 80 and 90 percent of the estimated 68 million refugees globally according to UNHCR figures were "in poor countries or have few resources."

Grandi added that Europe faced a "long battle" in reaching common ground on how to deal with the migrant issue but should cooperate in so far as possible and use the expected drop in numbers over the winter to draw up a coherent strategy.

In the meantime he added that the priority should be ensuring migrants reached the "nearest safe port."

That could not, he stressed, be Libya given that conditions in some reception camps there were "abominable, unacceptable."

Grandi said he was also concerned at the lack of rescue boats of Libya, be they humanitarian or military which meant not just less people brought ashore but also "more deaths."

Grandi further warned against politicians using intemperate language when discussing the migrant issue, urging that "the language of politics must not create a space for abuse and violence of a racist character."

On Monday, new UN rights head Michelle Bachelet announced a new team would be heading to Italy to monitor "a signaled strong increase" in racist violence, something which Italy's far right Interior Minister Matteo Salvini denied.

Salvini said that Italy had in recent years accepted 700,000 immigrants, "including many illegals, and never got any help from other European countries."